## JacquesC

Prof. Jacques Carette

## 2386 Reputation

19 years, 72 days
McMaster University
Professor or university staff

## Social Networks and Content at Maplesoft.com

From a Maple perspective: I first started using it in 1985 (it was Maple 4.0, but I still have a Maple 3.3 manual!). Worked as a Maple tutor in 1987. Joined the company in 1991 as the sole GUI developer and wrote the first Windows version of Maple (for Windows 3.0). Founded the Math group in 1992. Worked remotely from France (still in Math, hosted by the ALGO project) from fall 1993 to summer 1996 where I did my PhD in complex dynamics in Orsay. Soon after I returned to Ontario, I became the Manager of the Math Group, which I grew from 2 people to 12 in 2.5 years. Got "promoted" into project management (for Maple 6, the last of the releases which allowed a lot of backward incompatibilities, aka the last time that design mistakes from the past were allowed to be fixed), and then moved on to an ill-fated web project (it was 1999 after all). After that, worked on coordinating the output from the (many!) research labs Maplesoft then worked with, as well as some Maple design and coding (inert form, the box model for Maplets, some aspects of MathML, context menus, a prototype compiler, and more), as well as some of the initial work on MapleNet. In 2002, an opportunity came up for a faculty position, which I took. After many years of being confronted with Maple weaknesses, I got a number of ideas of how I would go about 'doing better' -- but these ideas required a radical change of architecture, which I could not do within Maplesoft. I have been working on producing a 'better' system ever since.

## Way too complicated...

Your code can be simplified to

`farey := proc(N::posint) local a,b; sort([op({seq(seq(a/b,a=0..b),b=1..N)})]) end proc;`

You were doing O(N^4) work when O(N^2) is sufficient.  Then with that you can do

```L:= N-> nops(farey(N)):
p1 := plots[listplot]([seq([n,3*n^2/L(n)],n=1..50)]):
p2 := plot(Pi^2,1..50):
plots[display](p1,p2);```

which is likely what you want.

## At least Maple-ify your question...

If you posted Maple input for your question, you might get more takers.

## ANOVA ?...

Robert is correct that rsolve won't help you at all here.  But it looks like you are really studying time series -- have you looked into the Statistics package instead?

## Pages to look at...

Look at ?plot,coords and ?plots,contourplot.

## Not always...

Some operations cannot be interrupted -- although most can.  Unfortunately, Matrix operations are one of those non-interruptible operations.

On the other hand, that Matrix is tiny, the context menus should be really fast for that (or at least they were for Maple 6, 7, and 8).  Which version are you using?  It is possible that some serious inefficiency has been introduced in the context menu code.

## Strange...

Maple 10 had all sorts of problems with Vista, but 11 seems fine.  I am writing this on a Vista laptop (woe be me, I know), but Maple seems fine.  Although I admit I most use Classic...

## What version?...

Are you sure you are running the same version of the MapleNet server as is used for this site?  [And don't assume that this site uses the latest version...  Maplesoft is very conservative in its software upgrades of important systems.]

## Definitely...

On expressions such as the one you gave, Maple's simplify should itself take care of trying radnormal.  It is surprising that it does not.  Have you filed a bug report?

## If you want an answer...

you need to tell us a bit more about your problem.  Just posting the one (huge) command is unlikely to motivate people to look at it.  And when a problem is so big, then using a worksheet with the justification and the command together is often a good idea.

## MathML !...

If you have the full MathType, I believe it understands MathML.  It used to be that Maple posted to the clipboard in multiple formats, including MathML -- at least Classic does/did.  Then you can just paste in the MathML.  If that doesn't work, then you can choose the 'convert to MathML' from the context menu, copy that, and paste it in.  Hopefully that will work.

## Avec MapleNET...

C'est possible de faire fontionner un Maplet en utilisant MapleNet, mais je dois dire que je ne me souviens plus comment.  C'est dans la doc the MapleNet.  Sinon il faut ecrire a Maplesoft (support@maplesoft.com), ils devraient pouvoir vous indiquer quelle partie de la doc il faut lire.

## Can't reproduce...

What version of Maple are you using?  In my Maple 11, I do not see those errors.

## Differential formulation...

Since you are doing kinematics, instead of using a moving frame [as you implicitly do in your formulation by putting some particles in a specifc location], use a fixed frame but do things in terms of the path of the atoms.  Your initial conditions will still be algebraic, as above.  But then your conditions will be in such a way as to give you a system of ODEs with conditions in exactly the way that the new numerical solvers can handle.

## Algebraic formulation...

One way to do this is as a system of polynomial equations and inequalities.  It is best to deal with the square of the distance instead of the distance itself [since that removes an unecessary square-root].

When you have a specific distance, then you can do something like `(a4-a3)^2 + (b4-b3)^2 + c4^2 = d23`, and inequalities in the same way.  Unfortunately, "resolving" such a system requires a CAD algorithm which, even after all these years, Maple still does not have.  Its main competitors do.

## diff...

My advice: learn how to do this by hand.  If you don't, you'll flunk your tests.

But if you want to check your answers with maple, then the command `diff` is what you are looking for.

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